If the aboveThis argument is omitted then the command raises
window so that it is above all of its siblings in the stacking
order (it will not be obscured by any siblings and will obscure
any siblings that overlap it).
If aboveThis is specified then it must be the path name of
a window that is either a sibling of window or the descendant
of a sibling of window.
In this case the raise command will insert
window into the stacking order just above aboveThis
(or the ancestor of aboveThis that is a sibling of window);
this could end up either raising or lowering window.

All toplevel windows may be restacked with respect to each
other, whatever their relative path names, but the window manager is
not obligated to strictly honor requests to restack.

On macOS raising an iconified toplevel window causes it to be
deiconified.

Make a button appear to be in a sibling frame that was created after
it. This is is often necessary when building GUIs in the style where
you create your activity widgets first before laying them out on the
display: